Here's a guide to removing, dissassembling and reassembling a Cannondale Super Fatty M Headshok -apologies for the length. I'm posting this so other people can see what I did to service my fork. I did not have a lot of money; my Headshok was bottoming out constantly and felt too weak on compression. Add to that my woes of getting dirt into the needle bearings and a torn boot, and I knew I had to do some work to it. I could, of course, have sent it off to Cannondale or gone to my local bike store (big Cannondale dealer) to get if fixed and rebuilt professionally..... but factoring in a new firm spring kit, boot, labour, etc, I think I was looking at a conservative $150 minimum.

Since I already had a spare 1 1/8 headset and stem, and Manitou SX-R forks (year 2000 model) can be bought on Ebay for around $90 (add in another $40 for headset reducer cups) including all shipping, if I was going to spend around $150, I would have spent it on the latter option. In short, money talks for me and my experience with Cannondales has taught me to prefer non-proprietary bike stuff. Oh yes, I know Manitou SX-Rs aren't exactly modern technology nor the best suspension, but neither is the Headshok Super Fatty M -and since I have an SX-R on my hardtail, I knew what the fork was like -its tunability, reliability and performance were all more than adequate for me.

THE GOOD STUFF
==============
It can be done. I did all work by myself with no help. It can be a one person job. It's not half as bad as people will lead you to believe, and the design of the fork holds no terrible secrets -conceptually it's actually pretty simple! A cautionary note though: I found the job to be pernickety in the sense you had to do some stuff in the right order, and it makes a difference if you do. All I can say is that the order I've listed is the order I found that worked for me, and usually there's a method in the madness for a reason.

Total cost for me to regrease, put a boot on, install new needle bearings and firm ride springkit and purchase any tools I needed: about $70. It took me about 8-10 hours in total to disassemble, reassemble, disassemble and reassemble again (includes thorough degreasing and cleaning). Admittedly, I do have some tools already, but everything else I needed I use in the general maintenance of bikes and is not Cannondale specific (e.g. hammer, Slick Honey grease, Pedros degreaser, etc).

CAVEATS
========
So this leads me to caveat number 1: basically I had nothing to lose. If I screwed up this fork or couldn't get if back together, it didn't really matter, I'd just go ebaying and get a set of adaptor cups and a used fork (also keep in mind I believe when you strip a Headshok, Cannondale may consider any warrantees null and void). My primary objective was to disassemble the fork and put it back together. If I could do this, I'd then invest in the necessary Cannondale parts and fit them myself. I had nothing to lose but time here.

Onto caveat number 2. Since I do not have access to top secret classified Cannondale documents regarding servicing/assembly of Headshoks, I am not privvy to torque specs or the like. This means that I put this fork back together the best way I could (Cannondale diagrams notwithstanding) using at best some guesswork and "common sense" ("common sense" here is very subjective I know. Let me reveal here I'm not a professional bike mechanic, nor am I a qualified mechanic in any area. What I have done is strip various car/motorcycle engines down and put them back together -working mind you!!!! -and my wife believes I have a natural aptitude for mechanics. Then again, she says I'm really good looking too ;^). I consider myself to be confident at mechanics..... confident in knowing when I'm out of my depth). The point here is that I'm just posting what I did -I am by no means suggesting this is the proper or appropriate way to safely reassemble a Headshok. So here you have it, caveat number 2: You mess with your Headshok at your own risk and this posting does not constitute in any way any endorsed ways of properly servicing or assembling or reassembling Headshoks. I am also not responsible for your costs or damages incurred, personal injuries, first born child, blah blah blah. It's all your responsibility and I can't vouch for the accuracy of this post or be responsible for any mistakes contained within.

Finally caveat number 3: I did my work on a Super Fatty M. I have no idea about any other Headshok models, they may be totally different as far as I know. The Super Fatty M is an 80mm travel spring/elastomer model with variable compression via an allen key adjustment after removing the top cap. It came as standard on my 2001 model year Jekyll.

RESOURCES
==========
OK, before I started this, I combed the internet looking for help. I googled, I yahooed, I did everything I could to search for any variation of the words "Cannondale Headshok Headshock assembly disassembly installation removal" etc. Let me tell you: there isn't much out there. And what there is, is hardly encouraging. Certainly Cannondale provides no technical help in the sense of stripping down a Headshok -just rather weak technical diagrams and advice such as "service at an authorized dealer every 40 hours of use". Hmmmm. Anyway, here are some helpful links I found:

Some of the common themes I found in the message boards are:
(i) don't take a Headshok apart
(ii) if you do, don't ever, ever, ever take apart the needle bearings and races.

Ooops, too late. I've always been a bit pigheaded anyway -and like I said, I had nothing to lose.

TOOLS
=====
old inner tube (700x23 was the best size I found)
scissors
small flat bladed screwdriver
zip ties
degreaser
Slick Honey grease (does not degrade elastomer stuff)
WD-40 (helped degrease parts)
Threadlok (missing from photo)
11mm open ended wrench
Green Park SPA1 pin spanner (had to buy this from my local bike store $9)
hammer
block of wood
allen keys
old front axle
vice and workbench (well lit!)
home fashioned castlenut tool out of old door hinge (used a hacksaw and file, as well as a hammer and vice to knock this into shape).
electrical tape
rags (missing from photo)
paper towels (missing from photo)
plastic ziplock bags (missing from photo)
outer race holding tool (fancy name for an approximately 15cm length of 700x23 inner tube with valve very close to one end, zip tied at both ends)

*worth noting here, for anybody in the greater Boston, Massachusetts area, I looked up the cost of needle bearings online, and found them for $27 at bikeparts.com. After calling three local Cannondale dealers, I found them in stock at Bikeway Source (http://www.bikewaysource.com/), Bedford, Massachusetts. I talked with Eric -a very nice guy -so I'm giving Bikeway a plug here for good service. Thanks Eric!

THE MECHANICKY BIT
=================
Just before I delve into my step by step on how I disassembled and reassembled, I want to add I will call parts by the names designated on the Cannondale technical diagrams. If they are not identified on the diagrams by Cannondale, I'll do my best to describe what I'm referring to. It might be a good idea to have the Cannondale technical diagrams printed out in front of you. I did not find any left handed threads on any of the parts.

SUPER FATTY M -OVERVIEW (YOU NEED TO READ THIS...... NO REALLY!!!!!!)
================================================== =========
Let me try to do this as succinctly as possible: conceptually, you can think of the Fatty M as two cylinders, one inside the other. In between the two cylinders are four sets of long rectangular needle roller bearings set equidistantly along the circumference of inner cylinder and lengthwise down the cylinders. These bearings allow the two cylinders to glide effortlessly between each other. Now, instead of these bearings hitting the metals sides of these cylinders directly, there are long metal strips (races) on each side of the needle roller bearings. Hopefully, you're still with me -look at the Cannondale technical diagram to get a better idea here:

Bear with me (oooh terrible pun) -remember I put at the title "YOU NEED TO READ THIS......NO REALLY!!!!!" -well this is the bit you need to know about: You have four long rectangular bearings. You have 8 races (four on the inner cylinder, four on the outer cylinder. These races are of fine tolerances -and like most things mechanical, you are best putting them back together the WAY THEY WERE PUT TOGETHER INITIALLY. So this means that however you disassemble or assemble the fork, you should try to keep the same races in the same position and orientation. Please, please, remember this. This should be engrained in your brain when you are working on your Headshok. I can't stress this enough (well, actually, that's not true, but it's the bloody easy way to do this, and you don't want the hard way). Of course if you screw this up like me......

A little side note here: I can't recommend enough that when you are working on something, if you have the opportunity to protect a part that is likely to be damaged by knocks or contaminants, take the time to protect it or remove it out of harms way. It'll save so much time in the long run and usually provide you with easier access and ultimately give you a much better temperament to work on things. On a nostalgic note, I remember my father showing me how it was so much easier to remove the hood/bonnet of a car to work on the engine if you were going to work on it for a long time. Thanks dad, a lesson learnt and not forgotten.

2. Remove top cap using allen key. Put aside safely in a clean box for the parts.

Another side note here: find a clean box to put parts in. I wish I could practice what I'm preaching here, but alas, I can't tell you how many times I've put a part down, and the "Small Part Pixies" come out with their magic dust and thieving grubby little hands -spiriting the part away right from under my own eyes. Putting the parts away safely makes it so much easier -I just really wish I could apply that myself!

3. Remove stem from steer tube.
4. Place a block of wood on the top of the steerer tube and tap it *gently* with a hammer. The fork should drop out of the headtube.

You should now have the fork in your hands (with brakes removed or protected, right?). The next step is to secure the fork so that you can work on it easily -remember, I said there was only one of me and it can be a one person job:

5. Remove the quick release skewer from your front wheel. Put this on your old front axle, and fix your fork to the front axle with the quick release as you would your front wheel. Next, place this axle with fork affixed in your vice (depending on the size of your vice, it might have to go in at an angle -which I actually found was easier anyway) and tighten. The vice should be clamped with enough force to prevent the fork from easily moving. You now have a makeshift way of freeing up your hands to work on the fork!

6. Cut the zip ties on the headshok boot, and remove the boot (cutting it off if your are going to replace it) or push the boot down. Again, I recommend wrapping the boot with a piece of cloth and securing it with electrical tape to reduce the chance of you cutting the boot while your are working.
7. Using the Park SPA1 pin spanner, unscrew the aluminium cap from the steerer tube. Be careful; you need to hold down the pin spanner to prevent it slipping (which it will do quite easily -and happened to me. I have a big scratch on the top of this aluminium cap -fortunately it is hidden by the top cap cover so it doesn't matter aesthetically. However, for future disassembly reasons, you don't want the two pin holes to become burred over so be careful). The fork should now slide freely up and down.
8. You should now see the aluminium cap attaced to a rod. To remove this cap, slide down the foam spacer, and use an 11mm spanner to hold the rod in place. Use the Park SPA1 pin spanner to turn the aluminium cap anti-clockwise. Place the aluminium cap in your box of parts.
9. Pushing down on the fork, you should now see the castlenut about a centimetre down in the steerer tube. To remove this castlenut I used a home fashioned tool out of a door hinge, but you could also use a bladed screwdriver. At this point, if the castlenut is on very tight, rather than burr the castlenut, it might be best to purchase the specific Cannondale castlenut remover tool (http://www.bikeparts.com/search_results.asp?ID=CA01146). I was fortunate, I found the castlenut came unscrewed with very little effort.
10. You should now be able to grasp the rod, and pull out the compression assembly with the castlenut. Put this safely away in your parts box (note: if you are upgrading the spring/elastomer to an air unit, the bottom cap at the base of the fork steerer tube is simply a compression fit and obviously needs to be removed as you'll have access to your air valve there. You can just use a socket extension and hammer to knock it out of the steerer tube if necessary).
11. Looking down the outer steerer tube, you should be able to see the four outer races (seemingly not secured in anyway but resting up against the thread at the top of the steerer tube) and inside the inner/fork steerer tube, you should be able to see your suspension spring (green=soft, blue=medium, red=stiff). You can use your Park pin spanner to hook on the spring to lift the spring and elastomer assembly out. Put away in your parts box. Now, if you look carefully at the top of the inner/fork steerer tube, you should be able to see the tops of four inner races -secured by a race retention clip (looks like a regular washer with four protruding tabs on the outside where the races are secured).

12. Remove the race retention clip using two zip ties and a small flat bladed screw driver.

OK. It's at this point I can proudly proclaim this was an original idea of mine. So much of the stuff I've posted is purloined and gathered from other links, but this one is all my own, so I'm "dead proud" of this. You can use the ends of the zip ties to jam down between the tops of the inner races and side of the tab on the race retention clip, forcing the race back and away from the race retention clip tab. If you do this with two adjacent races, you can then use the flat bladed screwdriver to push up the clip and remove it. Using this method, it took me all of five seconds to get the clip out. A word of caution here: I'm guessing that if you break the retention clip, you could be in trouble, so be gentle. This is also another advantage to using the plastic zip ties as it is less likely you'll brea`k that clip using them.

13. Move the fork gently up so you have access to the lower Headshok collar. Use the Park SPA1 pin spanner to unscrew this collar. Other instructions have noted this is secured with thread locking compound (mine unscrewed very easily however). Once unscrewed, I moved the collar as far down as it would go, and secured it by wrapping electrical tape around it.

Note: DO NOT MOVE THE FORK UP AND DOWN FROM NOW ON UNTIL SPECIFIED!!!! The races are now totally "unsecured" and will fall out if you pull up on the fork. You DO NOT want to do this yet!!!!!

14. Remember from the Super Fatty M overview I said: "keep the same races in the same position and orientation" -well, we're now at that bit where we need to secure the races so they all don't fall apart once we take the fork apart. One important thing here to help ensure everything goes back together exactly the same way -make sure you know which way the steerer tube goes on the fork steerer tube -this can be done by looking to see where the single vent hole goes in relation to the fork. The vent hole is a small hole that allows the air to escape from the suspension assembly. I secured my bottom inner races by simply tightly wrapping electrical tape around them. I also tried to use permanent marker to number the races and positions, but found that I could not get the races clean enough even for the permanent marker to take. I read you could use nail varnish to mark the numbers, but it wasn't my day to do my nails or get a perm, and hence did not have access to it. OK, with the lower inner races secured, we now need to secure the top outer races on the outer steerer tube. This is done by basically blowing up part of an inner tube inside the steerer tube, forcing the races to remain in place. It's really, really easy, and better still, works!!!!! Well, sort of.... read on for a cautionary tale:

I was really excited at this point. I'd read about using the piece of inner tube to secure the outer races (brilliant I thought, ingeniously simple), and was well versed in how important it was to keep the races in their original positions and orientations. I found an old inner tube I had (700x23) which I decided was to be my sacrifice to the Cannondale Gods, and cut it about 5 cm up from the valve. Next, I cut past the valve about 25 cm down. Feverishly and with great anticipation I zip tied both ends and test inflated it. Perfect! It looked like a dull fat Lancashire black pudding (sorry, reference here for northern English folk) about 25cm long . Feeling well chuffed with myself for being so fortunate to read about such a clever tip, I deflated it -and hurriedly put it into the top of the steerer tube about 10cm down and re-inflated. I was worried about the races moving, so I pumped it up quite well to make extra sure the fit was a snug one. Sounds good eh?

15. Once you have secured the outer races, pull apart the fork -as slowly as you can...... the aim here is to make sure the races stay in position. Keep an eye on lower inner races and if you can see them, the top outer ones. Eventually the fork will seperate, and you will see four long rectangle needle bearings in plastic sleeves come down in between the two races. As far as I know, it doesn't matter the orientation or position of the bearings with respect to each other -though I'd still try to put them back the same way they came out as a matter of course. I ended up fitting new ones as one of my bearings had broken so it didn't matter to me. You should now have three sets of parts: (i) a fork with lower inner/fork races taped on, (ii.) four needle bearing sleeves and (iii.) an outer steer tube with an cut off inner tube inflated and sticking out of the top.

OK, back to my little cautionary disaster story: I had those three sets of parts described just as above. I put down the outer steerer tube with inflated inner tube on my workbench to start degreasing and cleaning the bearings and inner races. Suddenly, there was a huge "POP!!!!" and then the sound of tinkling glass. My god, someone is shooting out the basement window! No.....the cut off inflated inner tube had split open, now looking like a forlorn floppy black rubber banana skin, and the outer races were randomly strewn inside the steerer tube. I said "Oh dear" and then added other far less than parsimonious words of the English language.

If you recall from my description, I had about 15cm of inner tube extending out of the steerer tube, and when I had pumped up the inner tube in my ardour to secure the races...... well the top bit had deformed grotesquely because of the air pressure, which of course had no tyre wall (or steerer tube) to help contain it. So here's my lesson learnt: use a lesser length of inner tube (about 10cm), and have as little protruding out of the top as possible -this way, the inner tube should not burst. Also, don't be over zealous with the inflation. So, my dilemma now was I'd royally screwed up the order of the outer races. How could I put them back together again in the right place and orientation? All I can say is that in the end, I tried looking at marks on the races and matching them up to marks in the steerer tube. Honestly, I'm really not too sure I put them back in the exact same place, but what I can say is that my Headshok is smoother now or is as smooth as the day I bought the bike. I suppose the moral of the story is that even if you do lose the positioning of the races, don't give up, it's worth guessing and using a bit of detective work to hopefully reassemble them in the right way. And even if you don't put them back in the original places, it doesn't mean the Headshok won't work.

16. Finally, you should now be free to liberally degrease all parts and get them clean. Cannondale recommends you inspect the steerer tube parts for fractures or damage (bit of common sense there I'd say).

STEP BY STEP -REASSEMBLY
========================
Assuming the fork is still secured in the vice.....

1. If you need to fit a new boot, remove the lower collar, and fit the boot over the fork steerer tube and push it all the way down. Secure the boot and protect it by wrapping a cloth around it (again, I secured the cloth by wrapping electrical tape around it). Check twice to make sure you have the fork boot the right way and replace the collar (once again, secure the collar and double check to make sure you have everything on the correct way!). One open question here: it would seem to me to be extremely awkward and painful to replace a boot without pretty much having to disassemble the entire fork -including the bearings. I tried to find the answer to this question online, but had no luck. It would be crazy if this were the case -but for the life of me I wouldn't like to try to force the boot over the outer steerer tube -which is a very tight squeeze and what you would have to do if you did not totally disassemble the fork. Since I was totally disassembling the fork, I can't say I spent too much time worrying about this -but if my boot splits in the future..... do I have to disassemble my fork again? I wonder.
2. Lightly grease the inner and outer races (I used Slick Honey -it will not degrade elastomers). I also lightly greased under the races to help prevent corrosion.
3. Using inner tube bands cut to about 1-2cm wide, place these over the lower races on the inner/fork steerer tube to further secure them. Place an inner tube band about 3cm down from the top of the inner/fork steerer tube.
4. Taking each of the four bearings, gently guide the needle bearing onto the inner race, and underneath the top inner tube band. Be careful here as the needle bearings are just plastic and delicate, and can be easily broken. Just so you know, the cross section of the needle bearing looks like a long thin rectangle -with the top left and top right corners chopped off. I doubt you can put them in the wrong way, but just in case, the longer flat length goes against the inner race, and the shorter top length goes against the outer race -as I said, I have a feeling you can't fit them any other way, but I thought it was worth mentioning just in case.
5. Each needle bearing should have about 11 needle roller bearings or about half the length of the needle bearing sleeve above the top of the inner/fork steerer tube. Once all four of the needle bearings are in place, lightly grease them (by not greasing them until they are secured, it is easier to work with them). I further secured the needle bearings by using electrical tape wrapped tight around. A tip here: for easy removal -which you'll need to do in a minute -leave the last of the tape sticking out so you can easily get hold of it.

6. Here's the tricky bit; putting the outer steerer tube together with the needle bearings and inner/fork steerer tube. Before you do so, quickly check all the races look like they are in position, and you might also need to put some more air in the inflated inner tube holding the outer races in position. Gently place the top steerer tube over the inner/fork steerer tube with the four bearings and gently pull down. Keep an eye on the inflated inner tube to make sure it is not being pushed out of position along with the outer races. You can also get a bit more grip on the outer races by squeezing the inflated inner tube.
7. Once you have about 2-3cm of overlap (you'll feel it if there is anything wrong) you can start to remove the electrical tape and cut inner tube bands to allow the outer steerer tube to slip down. Keep pushing down and removing electrical tape and inner tube bands until the needle bearings are enclosed in the inner/fork and outer steerer tubes. Again, be careful and do not be afraid to restart this process as the needle bearing are only in (fragile) plastic sleeves.

My experience with this: remarkably, my first re-assembly I did went like butter and I could not resist letting out a whoop of exhilaration and complete triumph. I had no problems at all, and in the end this process was mere seconds in doing. Interestingly, the next time I did it when I was installing new bearings, my outer races slipped, and I had to start again -and of course, now everything had a load of grease on it too which made it a little more difficult.....I uttered a more fitting "D'oh" per Homer Simpson. Still, even so, it only took minutes in total. I put this down to my liberal and very enthusiastic use of electrical tape to secure bearings and races, as well as a gentle squeeze on that inflated inner tube to help secure those top outer races.

8. Really, if you are this far, the hard bit has been done. The rest is just easy and pretty much just the reverse of the disassembly. To secure the race retention clip, push the fork down so the inner/fork steerer tube is within a centimetre or two of the top of the outer steerer. Using the same old zip tie and flat bladed screwdriver trick (see disassembly step by step), secure the tops of the inner races on to the four retention clip tabs. Using zip ties, it really can be done in seconds.
9. Replace the newly relubed spring/elastomer assembly into the steerer tube. Slip on the castle nut and tighten using a flat bladed screwdriver (or I used my own hand made tool). I was unsure of using thread lock here, so I didn't. The ease at which the castlenut unscrewed when I initially disassembled it made me think it was not used, and it's under compression anyway and not likely to unscrew itself. Again, not knowing torque settings, I tightened until if felt "right".
10. Using the 11mm open ended spanner, hold the rod of the compression assembly at the top, and use the Park SPA1 pin spanner to screw on and secure the aluminium cap. Once again, I did not use thread lock here, and tightened until it felt "right".

Interesting Super Fatty M note here: this connection from the rod to the aluminium cap became loose on my fork when I originally got it. I believe it occurred when I was trying to preload the spring too much, and I think it effectively forced the rod to turn clockwise (as I was looking down on it) thus effectively unscrewing itself from this aluminum cap. Maybe I should have used thread lock on this, I'm not sure. But I'm confident it's tight enough to not have this issue again, coupled with my new knowledge of the mechanical internals.

11. Rethread the lower Headshok collar onto the bottom of the outer steerer tube -make sure both threads are clean, and apply some thread lock. Tighten using the Park SPA1 pin spanner. As previously mentioned, I am unsure of the torque setting here. I just tightened until it felt "right".
12. Nearly there! Before we do anything else, we need to check to make sure the needle bearings are in position. This is done by checking the distance between the top lip of the fork to the bottom of the headshok collar. For Super Fatty M, we're looking for 74-79mm. Mine was a perfect 78mm. Here is the official Cannondale document that deals with this:

13. Finally, lube any exposing races, and reattach the boot and secure with zip ties. Make sure the headset races are nice and clean before putting the fork back on the bike. Replace top cap, fit in bike, reinstall stem, reconnect hardware and you're ready to ride.

I hope this post has helped. I wish it had been around before I started on my own Headshok servicing as (and I think you can tell) it was a learning experience for me as I went along. I've ridden the Jekyll since, and the fork feels fine, but of course, it may be I've done something terribly wrong -hopefully not -but would welcome any feedback or comments. One last thing I know I did do "incorrectly": you may pick up from the photos that the vent hole is positioned on the left hand side of the fork (a product of my exploding inner tube in that I lost track of it's relative position) -I believe it should it placed to the back of the fork. Since I tested it and it seemed to work (i.e. the boot isn't ballooning out with air pressure!) I'm guessing it's OK and I can hear the air being forced out..... so I made the decision to leave it as is.

Nicely done, wish I had the time to post that= The only issue I noticed in my admittedly semi rapid read through, was this. When putting the outer steerer back on, the bearings should have half above, and half below the top of the inner steerer. So when doing it, put 11 bearings above, all around. This gives an accurate travel amount. It appears that you will be limiting your travel, as you did it, and depending on how many were "below" when you reinstalled, it may just reset itself, due to the presence of the race clip. However, if you are the anal type, you may want to revisit it, as it will save you buying new bearings, cause yours got munched! Great work!

Thanks for the kind words (and I think it's fair to say you are the master!). It was one of those things where I really didn't have too much to lose given the economics of it. I really do like my Jekyll, and wanted to extend it's ride life.

Concerning the bearings, I did put somewhere in that rather overly long missive that 11 bearings or half of the bearing should be above the top of the steerer tube (in the pictures there are, though admittedly at first glance since I wrapped the bottom part of the bearings with electrical tape it may not look like it). I should have also noted I was particularly careful to have all the bearings 11 needles higher than the steerer tube. FYI as well, just one of my bearings -about 1-2cm down at the bottom broke off (maybe even when I was removing it?). I don't think I hit it, just not sure about it. Since the new set of bearings cost so little, I just replaced them all.

All in all, I'm really happy as for about $70 I'm back to a much smoother front shock, with a firm spring that is errr... well, more suitable to my middle aged mid riff. I was quite surprized at how many little gotchas I encountered -and how much easier it was if you did some of the little stuff (note here: when putting the outer steerer tube aside with the inflated inner tube, to prevent my kind of experience, also stuff in a rag to keep the races in place in case the inner tube burst! Yep, thought of that later). Lastly, I just love learning new stuff, and that gave me a big satisfaction to know I can adequately service my fork!

Originally Posted by MendonCycleSmith

Nicely done, wish I had the time to post that= The only issue I noticed in my admittedly semi rapid read through, was this. When putting the outer steerer back on, the bearings should have half above, and half below the top of the inner steerer. So when doing it, put 11 bearings above, all around. This gives an accurate travel amount. It appears that you will be limiting your travel, as you did it, and depending on how many were "below" when you reinstalled, it may just reset itself, due to the presence of the race clip. However, if you are the anal type, you may want to revisit it, as it will save you buying new bearings, cause yours got munched! Great work!

I like working on my own bikes. I was really pissed off when I came to the realization that Cannondale has this attitude that everybody's to stupid to work on their forks. I finally had it with my Super Fatty leaking even after it came back from the Canny factory freshly rebuilt. I was going to convert to a Fox fork so I felt I had nothing to lose too. I figured out how the thing worked after fabricating some tools very simular to those expensive ones that Cannondale sells and tearing it down. It's been a couple of months now and I haven't had any trouble with it but the next time I do I'm filming the whole thing. Then there will be a link posted as to where you can go for help. So there Cannondale. Sue me. It's the only way you'll ever get any more of my money.

I like working on my own bikes. I was really pissed off when I came to the realization that Cannondale has this attitude that everybody's to stupid to work on their forks. I finally had it with my Super Fatty leaking even after it came back from the Canny factory freshly rebuilt. I was going to convert to a Fox fork so I felt I had nothing to lose too. I figured out how the thing worked after fabricating some tools very simular to those expensive ones that Cannondale sells and tearing it down. It's been a couple of months now and I haven't had any trouble with it but the next time I do I'm filming the whole thing. Then there will be a link posted as to where you can go for help. So there Cannondale. Sue me. It's the only way you'll ever get any more of my money.

So, let me understand this, just cause it's kinda funny. You were sick of Cannondales attitude, which exists to make sure that the average non mechanical joe (not saying you are) doesn't kill themselves, or make their fork non functional(then hate Cannondale even more, for it). So you were going to dump their product for a Fox, who is even more tight lipped about their forks than Cannondale? I'm not getting the idea. Sorry, I'm not trying to poke at you, I just get frustrated when folks get all upset about this issue. Owning my own business, and working in shops for the last 20 or so years, I have seen sooooooo many guys who think they can do their own work, who come in with their tail between their legs, carrying a big box of loose parts, many of which are further damaged through the "repair effort" than when they came out originally. The kicker then is, it takes longer to put them back together, as you need to reorient everything into it's correct position, (something most people won't take the time to note, cause we're talking small tolerances here) and many parts that are now broken need replacement, and a $25 job goes into the $100 plus range. I take my computer to the computer store for service, but I do what I can for it, I take me truck to the mechanic, but I change my own oil, rotate tires, etc. There is no shame in having things done by someone else, that's what we're here for, and I'm fairly confident that without some sort of customer, you would not be able to make a living either= I am always happy to help those who want to do it themselves, but the caveat is this, you gotta be detail oriented, methodical, have the time, have a decent mechanical aptitude, and a willingness to tear it all apart again, carefully, cause you screwed something up. Cannondale doesn't want to exclude you, they just want you to love your fork, and have it working as best it can.

I get what you're saying. I know alot of people that would get into problems if they tackle a repair on their own. But I think the information or service documents should be available to help you understand this fork if you want to try. I want to love my fork too but when the damn thing needs repaired once or twice and in some cases more times per year and I have to send it in and be without the bike for no less than a week that kind of upsets me. It's a good thing I have more than one bike. I have a Fox fork on my other mtb and haven't had any trouble. Nada. I only have been screwing with the Headshok and nursing it back to health for some barrowed time. Cycling is an expensive hobby and I not only MTB ride, I Road ride too. I apologize if my rant seems a little to harsh but I buy bikes to ride not keep in service repair shops. Most of the dudes I mtb ride with who have Cannondales have removed there Fatty forks and replaced them with Fox. The only ones who haven't are the guys with a Lefty. I got an email from Magura about a new cartridge for the Headshok way back in the beginning of the year but haven't heard another thing about it since. I wonder how that's going. I will say one good thing about the Fatty forks, I like the lateral stiffness and the lightness, but that's it.

I get what you're saying. I know alot of people that would get into problems if they tackle a repair on their own. But I think the information or service documents should be available to help you understand this fork if you want to try. I want to love my fork too but when the damn thing needs repaired once or twice and in some cases more times per year and I have to send it in and be without the bike for no less than a week that kind of upsets me. It's a good thing I have more than one bike. I have a Fox fork on my other mtb and haven't had any trouble. Nada. I only have been screwing with the Headshok and nursing it back to health for some barrowed time. Cycling is an expensive hobby and I not only MTB ride, I Road ride too. I apologize if my rant seems a little to harsh but I buy bikes to ride not keep in service repair shops. Most of the dudes I mtb ride with who have Cannondales have removed there Fatty forks and replaced them with Fox. The only ones who haven't are the guys with a Lefty. I got an email from Magura about a new cartridge for the Headshok way back in the beginning of the year but haven't heard another thing about it since. I wonder how that's going. I will say one good thing about the Fatty forks, I like the lateral stiffness and the lightness, but that's it.

I still have a 7 years old Fatty SL, had my LBS do maintenance a few times (less than once a year and it doesn't take them a week either), never too expensive and the forks still works like a champ. They are much more reliable than any other forks I have experience with. If you prefer Fox forks because they are more to your style, then go ahead and get a Fox. Headshoks are short travel stiff forks and thus have their limitations but they are great for their intended use and are stronger than bulls.

With that said, even though I'll still let my LBS do the work if the fork needs it, this is nice work and good reference Nigeyy!

I get what you're saying. I know alot of people that would get into problems if they tackle a repair on their own. But I think the information or service documents should be available to help you understand this fork if you want to try. I want to love my fork too but when the damn thing needs repaired once or twice and in some cases more times per year and I have to send it in and be without the bike for no less than a week that kind of upsets me. It's a good thing I have more than one bike. I have a Fox fork on my other mtb and haven't had any trouble. Nada. I only have been screwing with the Headshok and nursing it back to health for some barrowed time. Cycling is an expensive hobby and I not only MTB ride, I Road ride too. I apologize if my rant seems a little to harsh but I buy bikes to ride not keep in service repair shops. Most of the dudes I mtb ride with who have Cannondales have removed there Fatty forks and replaced them with Fox. The only ones who haven't are the guys with a Lefty. I got an email from Magura about a new cartridge for the Headshok way back in the beginning of the year but haven't heard another thing about it since. I wonder how that's going. I will say one good thing about the Fatty forks, I like the lateral stiffness and the lightness, but that's it.

Sounds as though you had a dud fork, these things happen. What's inexcuseable is that your shop could not fix it in house, and that Cannondale is over-run with forks, and unable to keep up. The problem stems from having a product that requires working knowledge, and most shops have mechanics who are in high school or college, and leave the industry for a "real" job, taking all the accumulated knowledge with them. So, the shop has to start all over again, retrain a new crew, and have half of them be out the door at seasons end. It's a real problem, and until bikes are taken as a serious sport and business, instead of "pastime toys", we will not see wages commensurate with folks willingness to make it a career. The last shop I was at, had me for 8 years, before that 5 years, so I have that accumulated knowledge, and experience, and it drives me to drink that there are all the shops out there that have crappy or nonexistent service for what they sell, beyond tune-ups and flat repairs. As for Fox, they require you to send it in too, no shop anywhere is authorized to do many things inside their product, just so you know. I have several customers who ride them, and love them, but they have had their own host of things that go wrong, and cost good money to put right. Ride them long enough, and you'll be there too. My advice for your existing headshock is, find a good shop, or send it to me, and I'll put it right. Even if you did it yourself, you may not find the small issues that are causing your problems. Most of these forks go for 2,3, or even more years with nothing done. Not even the prescribed 40 hour service (which is excessively short in my opinion). A yearly service once the fork is right, should be do-able by you, and that will keep her running. Also, I hear OUTRAGEOUS quotes for service on these, I think this post even mentions $150 plus, most full replacement rebuilds cost sub $100 here, and routine teardown/lube service is $25. Best of luck, ride hard.

Holy Shiite!

No, really it's not -I'm pretty sure I could strip my fork entirely down in about 30 minutes, and probably put it together in an hour or less now. I did not find it anymore difficult than some Manitou forks I've stripped -just initially time consuming as I had to stop and think how best to proceed or take extra care since I was not familiar with the fork. I was being extra, extra careful. I cannot stress enough the fork design is actually conceptually very simple, and once you do it once, it really isn't that difficult.

I admit my description was (cough) a little wordy, but I tried to put absolutely everything in there I learnt in the hope it might help someone else out. I'm hoping someone could read that and pretty much be able to do the same without any errors or costly mistakes at all as I -at least I think I did -covered all the bases. I'm not going to claim I'm an expert technical writer (ha, obviously I'm not!!!!), but if you think about describing even how to tie a shoelace to someone who's not done it before, you might be surprized how much detail you might have to write down.

Oh no, I didn't think think you were complaining about what I wrote, I was responding to the fact you might think the process is a big pain.... Once you strip away all the little niggling details (which make that post I wrote so long), it's overall a pretty simple straightforward thing to do. Sorry, definitely didn't mean to come across as sounding sensitive!

Originally Posted by Elzippo

I wasn't complaining about your thoroughness.
An overall a great job writting this up indeed, with pictures to boot!

So, my Super Fatty is showing signs of needing tore down again. Just a few months of riding. It's doing that clunking thing when it tops out. The Canny website tech notes state to check for bearing migration. Did that. The measurement is right in the middle within tolorances. So. Does it get sent back to the factory or what? I'm dropping two $200 or more a year just in this fork. Does Cannondale employ high school mechanics too? Is my fork being checked out properly at the factory?I question the quality of the work. The fork work well for a few months that's it.

I'd be interested to hear more about what you are experiencing. Since I now have a much better concept of how the Super Fatty fork works, I'd be curious to see what the issue is. Do you have the elastomer/spring fork? Or the air cartridge? What weight are you, and what kind of settings do you run? (E.g. what colour spring?). What are the symptoms exactly? Kind of riding?

I know it's a bit of heresy on the Cannondale site, but if you are spending $200 a year on this fork -or even over a couple of years -I think you should consider getting a "regular" fork. I thought long and hard over this option -particularly a Marzocchi MX fork as I only do XC. Failing that, I'd definitely recommend working on the fork yourself to save some time and money.

I'd be interested to hear more about what you are experiencing. Since I now have a much better concept of how the Super Fatty fork works, I'd be curious to see what the issue is. Do you have the elastomer/spring fork? Or the air cartridge? What weight are you, and what kind of settings do you run? (E.g. what colour spring?). What are the symptoms exactly? Kind of riding?

I know it's a bit of heresy on the Cannondale site, but if you are spending $200 a year on this fork -or even over a couple of years -I think you should consider getting a "regular" fork. I thought long and hard over this option -particularly a Marzocchi MX fork as I only do XC. Failing that, I'd definitely recommend working on the fork yourself to save some time and money.

Hey. I wasn't whinning about the problem with the fork, I just wanted to post an update as to the frequency of the problem with the Super Fatty Air Cartridge Fork. The last time I had it rebuilt by Cannondale, back in late summer early fall last year it leaked oil constantly until it had about a one inch drop or play at the top end when in lockout. My shop guy said it was low on oil so I learned how to fill it myself. Funny, it quit leaking after that. Now it's been about six months with only maybe a dozen rides in that time period and it's cluncking at the top end. It hits pretty hard too. I weigh 180lbs. I put enough air in it so that it doesn't bottom out and I get just a little sagg when I sit on the bike. The terrain I ride is mostly singletrack with switchbacks and log obstacles to hop over. Some fast fire roads and of coarse the occassional washed out rut on the trail. No rock gardens or jumps. I have a Specialized FSR Enduro for that ruff stuff. And I tend to ride it alot more than the F700. Getting older and riding the trails gets harder on the back when you ride a hardtail. But, the bike is a 2001 and still looks faily new and in great shape so that should tell you I don't abuse it. This fork is just a piece of junk. I thought of putting the new Magura cartridge in it but I think that it's around $350 but I haven't heard any reviews about it. I would spend the money in a minute if I knew most of the maintenance issues would end. I took it apart again today and guess what I found loose inside. There's a small O-ring about 1/2" diameter laying in the bottom. I can't figure out where it goes. With no drawings available I'll never figure it out either. Unless someone here knows, it's going back to Cannondale again.

Hey. I wasn't whinning about the problem with the fork, I just wanted to post an update as to the frequency of the problem with the Super Fatty Air Cartridge Fork. The last time I had it rebuilt by Cannondale, back in late summer early fall last year it leaked oil constantly until it had about a one inch drop or play at the top end when in lockout. My shop guy said it was low on oil so I learned how to fill it myself. Funny, it quit leaking after that. Now it's been about six months with only maybe a dozen rides in that time period and it's cluncking at the top end. It hits pretty hard too. I weigh 180lbs. I put enough air in it so that it doesn't bottom out and I get just a little sagg when I sit on the bike. The terrain I ride is mostly singletrack with switchbacks and log obstacles to hop over. Some fast fire roads and of coarse the occassional washed out rut on the trail. No rock gardens or jumps. I have a Specialized FSR Enduro for that ruff stuff. And I tend to ride it alot more than the F700. Getting older and riding the trails gets harder on the back when you ride a hardtail. But, the bike is a 2001 and still looks faily new and in great shape so that should tell you I don't abuse it. This fork is just a piece of junk. I thought of putting the new Magura cartridge in it but I think that it's around $350 but I haven't heard any reviews about it. I would spend the money in a minute if I knew most of the maintenance issues would end. I took it apart again today and guess what I found loose inside. There's a small O-ring about 1/2" diameter laying in the bottom. I can't figure out where it goes. With no drawings available I'll never figure it out either. Unless someone here knows, it's going back to Cannondale again.

That O ring most likely came from the bottom of the cartridge where it threads into the fork. That is the only readily accessible O ring in there. All the others are internal to a certain degree. It sounds as though whoever did your work did not replace the seals all around. As many have said here, this is one of the more "ride it and forget it" forks made by Cannondale. That said, if you can get the cart out yourself, order an "All seal" kit from Cannondale, through your LBS, and install all of it you can. If your work is good, and all the internals are in GREAT shape, no nicks or scratches in the shaft etc, yopu should be fine from there. I have had forks that leak oil after a rebuild, and replacing the seals will square it away. Sorry to hear of your troubles, that should not be the case, and underscores my point about shops being able to service them in the field. If Cannondale has to handle 90% of the forks they have ever made, cause their shops to a large degree suck, than you can bet Cannondales service will suck too, based on volume related pressures. Good luck!

That O ring most likely came from the bottom of the cartridge where it threads into the fork. That is the only readily accessible O ring in there. All the others are internal to a certain degree. It sounds as though whoever did your work did not replace the seals all around. As many have said here, this is one of the more "ride it and forget it" forks made by Cannondale. That said, if you can get the cart out yourself, order an "All seal" kit from Cannondale, through your LBS, and install all of it you can. If your work is good, and all the internals are in GREAT shape, no nicks or scratches in the shaft etc, yopu should be fine from there. I have had forks that leak oil after a rebuild, and replacing the seals will square it away. Sorry to hear of your troubles, that should not be the case, and underscores my point about shops being able to service them in the field. If Cannondale has to handle 90% of the forks they have ever made, cause their shops to a large degree suck, than you can bet Cannondales service will suck too, based on volume related pressures. Good luck!

Good news. I tore down the fork this morning. I found that the rings, seals, o-rings had somewhat expanded or swelled and were barely doing their job. Now, either Cannondale did not replace the seals when they rebuilt it or the fork oil I used the last time I topped it off destroyed em. I tend to think it may be the oil. I say that because I used a syringe for filling and the rubber plunger swelled. I got another new syringe and it did it again. Why would fork oil do that? I got the oil from a motorcycle shop. Anyway, I went to the bike shop and bought a new seal kit and some different oil. I figured out where that small 3/8" to 1/2" o-ring went. There is a plastic ring that fits on the top of the spring in the air chamber. The o-ring fits between that plastic piece and the bottom of the oil chamber. I got it all together and bled and it works as good as new. I got the bearings greased and now it's ready for action again. The seal kit was only $8. Why then does the Factory charge so much? As I remember Cannondale charges something like $65 for that. Then the bike shop added their take $45 for putting the fork back on the bike. I'm glad I learned how to do the job myself but without the documentation it was stressfull.

Why then does the Factory charge so much? As I remember Cannondale charges something like $65 for that. Then the bike shop added their take $45 for putting the fork back on the bike..[/QUOTE]Cool, glad it all worked out. I am not sure why the oil swelled your seals. The recommended oil is Golden Spectro, which is Moto oil, so , go figure???The factory charges so much, for the same reason dogs lick what they do, cause they can. It's obscene that they would do that to someone over a barrel, no shop in the area to fix your shock? We'll bend you over then, cause hey, someone has to! Then your shop charging $45 to install a fork, which takes about 5 minutes?? I am all about folks making a living wage, and shops charging rates comensurate with the level of professionality that a good mechanic deserves, but come on, let's also use our heads, hmmm, 10 minutes tops, TOPS, X $45= $270 hourly rate, I think there is an issue here. Fully certified Ferrari mechanics don't command that sort of price. You can do everything else, a fork removal will be cake. Don't give those folks a dime, they don't deserve it! Man, am I surly in the morning=

First of all, excellent job by Nigeyy on a tricky service. I'm a fully qualified auto technician and would love to strip down my fork next time it needs servicing. I have to say though the guy who serviced it in May only charged $50 including return shipping and I was very impressed with his work, sending me the old parts, a sheet with the work carried out, another sheet with maintanece instructions and set-ups, etc. If you do the sam job a number of times you will get very good at it - or very sloppy! As you've read here there are no big springs going to fly out and disappear down the back of the garage, just take your time and you can do it.

You need size specific shaft clamps and a bullet tool for re=assembly. That nut on top is press fitted and it's not supposed to come off. If you never did it I would highly suggest you send it in for a rebuild, because one wrong move and you will completely eff it up....a scratch on the shaft and you'll have constant oil leaks....

anyone recognize this Headshok cartridge?

I am new to the forum so I am not allowed to start a new thread without 5 posts. Instead I''l try to attach my question to this old topic.

I have researched this for hours. I have a C. F600 which I bought in '04. The Headshok recently went south so after viewing several web sites that demonstrate repairs I decided to tackle this (replace o-rings) on my own. Bottom line; after disassembling the unit I find it looks quite different from all the examples I have previously viewed. I seem to be close to being able to do this if I could only get a couple of questions answered. Instead of inquiring at this point I shall just ask if anyone knows of this particular cartridge and, if so, I shall proceed.
PS. There is no spring nor elastomer evident.

Wow, thanks Mac, that's it! It is the first real foto of that particular model I've seen after hours of googling. The others have had colored cannisters or different configurations at the base.

You are correct on the spring. Shortly after I posted this I turned the fork upside down and, sure enuf, out fell the spring and then the entire air cartridge. Sweet!

My question then:
How can one remove the top white plastic threaded plug of the oil chamber through which the damper rod passes? I suspect there is an o-ring inside of it which could be a source of an oil leak. That plug is located between the large black stem cap above and the series of "washers" of the lockout valve (halfway down the rod) below. Neither the black cap nor the lockout mechanism seem to be removable from the rod. Since I had lost damper oil I would like to replace all the critical o-rings where a leak to outside of the cartridge could occur and the top plug seems critical. Every movement of the damper rod involves that passage thru the plug.
Did your service include replacing o-rings including that possible one inside the top plug?

All I did was an inspection, clean and oil change. I didn't bother changing any seals as there were no leaks or problems with the fork.. in situations like this I like to follow the golden rule - 'if it an't broke, don't try and fix it'

To get access to the upper oil cap you have to separate the damper shaft..

Please be aware that you absolutely require specialist tools for this particular job or else you will make a dog's dinner out of your damper shaft.. Do not DIY a tool to hold the damper shaft.. just get the right tool for the job because one small scratch on the shaft and your in a whole heap of trouble.. and expensive trouble at that..! The tools are inexpensive compared to a new damper..

You need 1/2" shaft clamps.. this tool is essential to hold the shaft safely without scratching it..

Also, I would recommend you do your homework thoroughly before trying this.. so you are aware of the steps involved and the risks.. I'm not qualified or experienced enough to talk you through it so I don't want to give you the wrong advice..

I hear you loud and clear re: causing damage. However I don´t consider my Headshok sacred and if I screw it up I´ll either go ¨shockless¨ or replace it with another brand fork. I just don´t like the idea of being held captive by Cannondale; by their way of restricting access to repair information and proper tools. This is not rocket science.

I may just replace the easily accessible o-rings and call it good but I am curious about the assembly and especially since Cannondale has make it a top secret that only a few select and priviledged share. Thanks to people like you the ridiculous secrecy is somewhat open.

That said, and a hearty THANKS for the tool links, could you tell me just where it is the damper shaft separates into two? Is it at the top black steering tube cap or just below the lock out mechanism half-way down the shaft? I assume one part unscrews against the other.

FWIW, it's not ridiculous. The consuming public at large, often is though.

By not making all info public, they protect the great unwashed (a little bit), from their own overzealous, cheap minded DIY efforts, which invariably ends with them calling Cannondale and screaming warranty, or the thing falls apart on the trail, they lawyer up, and Cannondale has to defend themselves.

Not saying anyone in particular here would do that, but I can't tell you the number of mangled piles of parts I get in boxes from hand wringing anxious riders who tried to DIY....

So I ride my Cannondale knowing that it has a rather delicate fork mechanism with a rather high probability of failing, will cost a rather large sum of money, hassle and time to get fixed and for which I will be considered guilty of trespass if I want/try to maintain it myself. So much for self reliance and independence. What kind of sport is this?

You know, that logic could be applied to about any product out there. Hands off - too dangerous to do yourself - let us take care of it, or else. How about a flat tire?

I am aware of the risks of messing up the repair and am willing to pay the consequences. Hey, more money for the bike shop. But I question the idea that this piece of equipment is too sophisticated for me to deal with (given the proper diagrams and tools) or that repairs of equipment I have paid dearly for (> $1000 in ´04) become an ongoing financial drain with just average usage.

Sorry but I stick with my opinion that $150 to have repaired/maintained a rather simple device is excessive and unnecessary.

[QUOTE=fredf;9837988
That said, and a hearty THANKS for the tool links, could you tell me just where it is the damper shaft separates into two? Is it at the top black steering tube cap or just below the lock out mechanism half-way down the shaft? I assume one part unscrews against the other?
Fred[/QUOTE]

Yes, they are....the lower damping shaft has a slots for an open end wrench...(a special...really flat one)....hold the top part of the damper shaft with shaft clamps and unscrew the lower one....once separated you will be able to take it completely apart....I used to hold the lower shaft with a shaft clamp and and used an adjustable wrench on the lockout knob on top to undo the shafts...I was told that this might damage the lockout, but if done carefully enough it will be ok and I never had issues because I did it that way...make sure you use appropriate loc tite when you reconnect the damper shafts!

cdalemainiac:
That is what I suspected re: the rod disassembly. Thanks for confirming it. Now I can access all the critical parts for o-ring changes which should solve the damper oil leak that has rendered my Headshok useless. Since the bike has low only highway miles everything inside the shock looks brand new so I guess the rings just deteriorate over the years regardless of usage.

MendonCycleSmith:
Nope; I am going to vote Libertarian.
My local shop quoted me at least $150 to send the shock to CDale. They won´t touch it themselves (why is that; intimidation?) and they are the ones that sold me the bike.
Me the whiner? I began by soliciting advice for doing my own repair and was happy learning what I needed to know from a couple of members. I suspect you could have also helped but instead apparently you took my negative comments re: Cannondale personally. Sorry about that but after reading scores of complaints about CDale´s policies and practices I know I am not speaking out of line.

MendonCycleSmith: I suspect you could have also helped but instead apparently you took my negative comments re: Cannondale personally. Sorry about that but after reading scores of complaints about CDale´s policies and practices I know I am not speaking out of line.

Sorry, just way overextended, too much on my plate at the moment. I have personally answered these same questions more times than I can count on here, hence the sticky at the top, with all manner of Tech threads, all in one place. There is also scads of threads scattered about this forum, and searching will turn them up.

It's frustrating to have yet another person blame Cannondale for not making it easy to DIY, when I see so many of the DIY efforts turn to crap in a box, and hatred for the brand.

Too many people are cheap, won't buy the tools because they are just positive that the Vice Grips will work just as well, then use improper parts, damage things without knowing it, then go on the internet and blame the brand, instead of themselves for screwing it up.

Thanks for the apology. Obviously you are an important contributor to this forum - I would rather be with you than against you.

The info you have pinned to the start of this topic is useful but, again, is not that of my particular cartridge. I have not run into fotos or diagrams of mine yet.

What I really need is a detailed breakaway diagram of my damper components. The verbal descriptions are useful but often lack some critical detail. It appears that the CDale manuals with drawings that were previously accessible to the public are no longer so. I guess I shall just have to proceed one tiny step at a time asking questions and be glad that I can get answers at all.

The info you have penned to the start of this topic is useful but, again, is not that of my particular cartridge. I have not run into fotos or diagrams of mine yet.

It's the same function wise as any of the lockout dampers of the era. There are two types with oil, the 5 position damper dial, and the lock out. They may vary slightly in appearance, but are the same at heart.

You'd need an arbor press and the correct tooling to push the damper shaft apart, and reassemble. The nut at the top holds it all together, and is pressed on, it does not have threads.

You'd need an arbor press and the correct tooling to push the damper shaft apart, and reassemble. The nut at the top holds it all together, and is pressed on, it does not have threads.

Only if he wants to remove the threaded top cap though....the damper shafts are connected via threads.....the nut will only turn so much (lock out disengaged) and you will be able to undo the shafts....once apart the rebound rod will be accessible, along with all other parts in need of new o-rings.
Always worked fine on my fatty cartridges and my dlr2 damper as well if not put together correctly though you will end up with your lockout in reverse order like somebody here on this forum mentioned before. Despite what some folks say this is possible as it happened to me as well.
Meaning: counterclockwise=locked out, clockwise=open